1. Field
The invention relates to apparatus having programmable microprocessor control. More particularly, the invention pertains to the electronic operation, diagnosis and analysis of the control systems of sterilizers.
2. State of the Art
In the past, sterilizers have utilized electronic microprocessors for controlling the operation of the machines in prescribed sequential phases such as power-on, evacuation, sterilant introduction, processing/sterilizing, purging, and cycle completion. Each phase normally includes a number of discrete operations. In normal operation, certain conditions such as sterilization time and temperature can be preset by the user.
Diagnosis to determine the cause of apparent aberrations has generally comprised running the sterilizer through complete cycles while observing the operation. Often, the diagnosis consists of an educated guess as to the cause of the aberration. After each attempt at repair, the sterilizer is operated through a number of complete cycles to determine if a proper repair has been made and the machine is operating properly. As a result, the diagnosis, repair and testing has been a time-consuming operation, with most of the time often being consumed in performing functions unnecessary to the actual repair of the sterilizer. Furthermore, additional hook-ups to sensing and control circuits have often been necessary to obtain temperature, pressure, and/or other data not indicated or printed out in normal operation.
Testing during and following the manufacture of a particular sterilizer unit has been typically performed by operating the unit through one or more complete cycles at each standard condition of sterilization time and temperature, etc. It has been necessary to perform such manual operations as opening the chamber door between each cycle, for example. Typically, testing of the sterilant "dump" operation, in which sterilant is introduced into the chamber, has included long waiting periods while the remainder of the cycle phases were being run. "Homing in" on a particular phase of the cycle, or a particular step of the phase, generally included long periods of unproductive trial and error operation.
The need for an improved method and apparatus for diagnosing the operation and equipment integrity of sterilizers and the like has long been apparent.